Artificial tooth



g- 8, 1939- H. w. HANKINSON 2,168,953

ARTIFICIAL TOOTH Filed Oct. 23, 1936 Patented Aug. 8, 1939 UNITED STATES PATENT OFFICE 3 Claims.

This invention relates to improvements in artificial teeth and particularly anterior bridge teeth and comprehends means for attaching porcelain bodies or facings of individual teeth to the metal backing, and this assembly to the denture material.

The primary object of the invention is to provide an artificial tooth for either fixed or removable bridge work of such a character that no gold will appear from the anterior aspect, and. at the same time the assembly is of unusual strength and particularly natural and translucent in appearance.

Another object of this invention resides in providing a structure of this character which is replaceable when necessary without the replacement of the backing or other bridge part.

Still another object resides in providing an artificial tooth of such a structure that it may be ground on either the gingival or incisal edges to more exactly fit the individual case and without interfering in any way with the backing.

Other objects and features of the invention will more clearly hereinafter appear by reference to the accompanying drawing, specification and claims forming part of this application.

In the drawing: Figure 1 is a vertical section of one form of the invention. Fig. 2 is a perspective view.

Fig. 3 is a perspective of the backing plate removed from the facing.

Fig. 4 is a vertical section of a modified form. Fig. 5 is a perspective with the plate removed. Fig. 6 is a top plan view of the plate and Fig. 7 is a perspective view of the plate.

Referring first to Figs. 1, 2 and 3 in the present illustration the artificial anterior tooth is illustrated and includes a body I, formed with the gingival edge 2, the incisal edge 3 and the lingual surface 4, the latter surface flaring outwardly to form an intermediate thickened portion 5 having the inclined shoulder 6 which terminates at the vertical wall portion 1. The vertical wall portion extends upwardly for a short distance and then is curved inwardly and upwardly at I forming the inner face of the gingival edge 2. From the lingual surface 4, about the junction of the middle third with the gingival and incisal third a vertical slot 8 is formed in the body of the tooth. This slot 8 is positioned centrally of the transverse structure and extends through the intermediate thickened portion. This flat slot 8 extends into the tooth only to about the middle 55 of the distance between the lingual and labial surface 9 where it connects with the vertical groove In, the latter being oval or similarly shaped in cross section and of greater diameter than the slot 8 and forms the inner enlarged extremity of said slot. This enlarged groove I0 which defines the inner extremity of the slot 8 extends toward the incisal edge at H for a greater distance than the slot 8 and forms with the slot a cavity of substantially T-shaped cross section. The particular shape and formation of the tooth provides a structure of exceptional strength in resisting the stresses and strains to which a tooth may be subjected.

The backing which fits and cooperates with the tooth and is secured thereto by a suitable cement includes a wall structure complemental to that of the inner face of the tooth. The backing plate includes the vertical portion l2 which engages the vertical portion of the flared wall 5 of the tooth, the intermediate inclined portion l4 0 which seats upon the inclined shoulder 6 and the short vertical portion 15 which abuts against the vertical wall portion 1 of the tooth. Fixed centrally of the backing plate and extending inwardly therefromat substantially a central point is the web I6, the lower wall I! of which terminates flush with the lower edge of the vertical section l2 of the backing plate. The upper edge of the web engages the inner face of the inclined wall portion I4 and this web is made integral with the backing plate throughout the contacting surfaces. The web I6 is formed along its free vertical edge with a bead or pin structure I! of suitable size and shape to snugly fit within the slot I0 formed within the tooth. This beaded edge is in the nature of a pin and corresponds in length and diameter to the slot ll) of the tooth structure. The slot ll] projecting below and above the slot 8 necessitates the extension of the pin below the web l6. This pin I! is preferably formed with a roughened surface to facilitate the binding action when cemented in place.

Referring now to Figs. 4, 5, 6 and '7 a further development of the inventive thought is illustrated. In these figures the main tooth portions are indicated by similar reference characters as in the disclosures of Figures 1, 2 and 3, namely, the body I, housing gingival edge 2, incisal edge 3 and lingual surface 4. The general assembly ap pears similar to an ordinary plate tooth with the exception of the lingual surface 4 which is formed with the inclined face 20 and this surface has a normal anatomical contour to the occlusal surface. Extending vertically and midway of the inclined surface 20 is the transverse slot 2| having enlarged inner grooves on extremity 22 and this groove is positioned as in the prior form to receive complemental backing structure shown clearly in Fig. 7. This backing structure consists of inclined plate 23 for seating on the surface 23, triangular downwardly extending centrally located metal plate 24 for seating in groove 2i, and pin 25 fixed on the inner vertical edge of the triangular plate 24 for seating in groove 22. These parts are formed as an integral structure. On the top of the plate 20 is the anchor element including the fiat elongated body 26 supported and spaced from the top of the plate 20 by means of legs 2? located adjacent each end. This structure is fixed or integral with the plate and in elevation forms a double T-shaped assembly with an open upright. The nature and structure of this pin may be varied as desired, provided suitable anchorage for retentive purposes is comprehended. The connection of the backing plate to the tooth is identical to those of the other form.

In assembling the structure of Figs. 1, 2 and 3, it is customary to solder or otherwise secure the backing plate to the removable bridge work and this connection is between the face of the upright wall portion l2 of the backing plate and the bridge or other dental structure to which it is to be attached. After the attachment of the backing plate to the dental structure the tooth or facing t is secured by the use of cement, i. e., cement is placed in the slots 8 and I and the Hi and bead or pin l! are forced into the respective slots 8 and IE). In assembling the modified structure as contained in Figs. 4 to 7 the practice is identical.

The backing is constructed of metal which is strong and which will not be affected by the condition or acids of the mouth nor by the materials used in constructing dentures. As heretofore stated the backing fits into corresponding grooves into the facing and is cemented or otherwise secured in place. The facing and backing is then used in constructing dentures the same as with any other plate tooth. The main advantage in this artificial plate tooth over others now in use is that the tooth in denture if broken, may be replaced quickly by cementing another facing to the backing, thus eliminating the delay which has heretofore been customary while a new tooth is being vulcanized into a plate. Particular emphasis is placed upon the fact that in the present backing for both anterior and posterior teeth it is possible to use the same for bridgework by leaving off the retentive pins or plates 262'I, which latter are designed particularly for plate Work. These elements 262l are illustrated as part of both modifications.

It will be noted that in the first form of the development the disclosure including the vertical wall portion l5 of the backing and the cooperating wall portion 1 of the tooth is adaptable in connection with bridge work, but may be omitted when the assembly is used in plate work. In the latter instance the inclined face 6 of the tooth will continue uninterrupted to merge with the wall portion 1. Likewise when the backing wall portion I5 is omitted the inclined section M will extend to overlap the upper extremity of the pin ll, thereby forming a plate conforming to the modified tooth structure.

What I claim as new and desire to secure by Letters Patent is:

l. A backing for artificial teeth including an inclined intermediate portion and vertical portion depending from the lower edge of the inclined portion, a short vertical portion extending upwardly from the upper edge of said inclined portion, a web depending from the inclined intermediate portion, said web terminating at its free vertical edge in alignment with its upper edge of said inclined portion and at its lower end flush with the lower edge of the vertical depending portion, and a pin secured to the edge of the Web and projecting above and below the same, said pin being secured to said short upwardly extending portion and forming therewith a reinforcing means for said tooth.

2. The substance of claim 1 characterized in that the lower end of the pin extends downwardly below the depending vertical wall and the upper end of the pin abuts the short vertical wall edge and terminates flush with the same.

3. An artificial tooth formed of baked porcelain and including gingival and incisal portions,

an intermediate enlarged portion having spaced vertical upper and lower walls, and an inclined intermediate wall connecting the vertical wall portions, a vertical key slot extending perpendicular to the occlusal plane, and a backing plate shaped to conform to the vertical and inclined walls of said tooth and including an inclined intermediate portion and a vertical portion depending from the lower edge of the inclined portion, a short vertical wall portion extending upwardly from the upper edge of said inclined portion and a web depending from the inclined intermediate portion, said web terminating at its free vertical edge in alignment with the upper edge of said inclined portion and its lower end flush with the lower edge of the vertical depending portion, a pin secured to the edge of the web and projecting above and below the same, said pin being secured to said short upwardly extending portion, and said pin and web forming a key for cooperation with the key slot in said artificial tooth whereby the parts are retained and reinforced in their respective positions.

HENRY W. I-IANKINSON. 

